Micro-level mechanisms of fiber waviness and wrinkling during hot drape forming of unidirectional prepreg composites. (December 2017)

• Record Type: Journal Article
• Authors: Farnand, K.; Zobeiry, N.; Poursartip, A.; Fernlund, G.
• Is Part Of: Composites. Volume 103(2017)
• Page Start: 168
• Page End: 177
• Publication Date: 2017-12
• Subjects: A. Polymer-matrix composites (PMCs) -- B. Defects -- E. Forming -- E. Prepreg processing; Composite materials -- Periodicals; Manufacturing processes -- Periodicals; Composite materials; Manufacturing processes; Periodicals; 620.11805
• DOI: 10.1016/j.compositesa.2017.10.008
• Languages: English
• ISSNs: 1359-835X

Abstract

Abstract: Fiber misalignment in composites in the form of in-plane waviness and out of-plane wrinkling, is a major defect arising from processes such as hot drape forming. This work studies the micro-level mechanisms of forming in-plane fiber waviness and out-of-plane wrinkling. An out-of-autoclave unidirectional prepreg system by SOLVAY (CYTEC), CYCOM 5320/T650-35 was used to conduct multiple forming experiments and study the effects of various parameters including forming temperate and lay-up sequence. The effect of partial impregnation, or 'Engineered Vacuum Channels', in out-of-autoclave prepreg systems on the intra-ply separation/slippage and consequently fiber misalignment was studied and found to be a significant contributor to micro-level mechanisms. Cross sectioning and microscopy of the parts and examination of the end termination profiles were used to analyze the effect of forming parameters on ply end-shortening and consequently fiber misalignment.